Looper control for sewing machines



NOV- 5, 1957 N. MARFoRlo 2,811,940

LOOPER CONTROL FOR SEWING MACHINES Filed May 21, 195e United StatesPatent O LOOPER CONTROL FOR SEWING MACHINES Nerino Marforio, Milan,Italy, assignor to S. p. A. Virginio Rimoldi & C., Milan, ItalyApplication May 21, 1956, Serial No. 586,096

Claims priority, application Italy October 13, 1955 1 Claim. (Cl.112-192) This invention relates to a control device for rocking loopersfor sewing machines.

It is a purpose of this invention to provide a looper control devicewhich causes the looper bit to travel Over a path adapted to improve thesewing operation.

A further purpose of this invention is to provide a control device ofthe type referred to, which is simpler and less expensive inconstruction than devices presently 1n use.

The improved looper control device for sewing machines comprises a rodto one end of which a looper is secured, means for causing the other endof said rod to rock over an arcuated path and a slideway for the rodfreely rotatable about an axis perpendicular to the rod axis andintersecting the latter.

The invention shall be described by way of example with reference to theaccompanying drawings, wherein:

Figure 1 is a diagrammatical front view of the control device;

Figure 2 is an end view of Figure l on a smaller scale, the device beingtted to the sewing machine.

The looper 1 is mounted on the end of a rod 2 hinged by a pin 3 to alever 4 rocking about a pivot 5.

The rod 2 is capable of sliding in a guideway 9 pro vided with anextension 9a, the axis of which intersects the rod axis, said extension9a being rotatable in a bearing 10 secured by means of a set screw 11 ina recess 12a in the frame 12 of the sewing machine.

A washer 13 held in position by means of a screw 14 axially screwed intothe extension 9a prevents removal of the extension 9 from the bearing.

The end of the lever 4 remote from the hinge pin 3 is formed with aspherical head 6 engaged by a spherical recess in a connecting rod 7driven in a known manner by a crankshaft 8.

15 denotes the plane of the cloth plate, 16 the path of the needle tip.

2,811,940 Patented Nov. 5, 1957 With the size and arrangement of thecomponent parts shown on the drawing, the tip 1a of the looper travelsover a path comprising a first portion denoted 17 comparable with an arcof a circumference of a large radius, the chord 18 of the are 17 beingat an angle of about 17 to the line 19 parallel with the path 16 of theneedle tip.

The second portion of the path of the looper tip is denoted by 20 and iscomparable with an arc of a circle having its centre at 21 slightlybeneath the plane 15 of the cloth plate and spaced by an extent A fromthe path of the needle tip smaller than the spacing B between said pathand the looper bit where the latter extends through the plane of thecloth plate.

What I claim is:

In a sewing machine comprising a frame, a needle reciprocated over arectilinear path, a cloth plate supporting the work through which theneedle path extends, and loopers, a device for controlling a loopercomprising a rod supporting at its upper end the looper secured thereto,a tubular guideway for slidably supporting said rod, a cylindricalextension on said guideway extending perpendicularly thereto and withits axis intersecting the axis of said rod, a bearing secured to theframe for rotatably supporting said extension, a pin at the lower end ofsaid rod having its axis parallel to that of said cylindrical extensionbut being provided at the opposite side of the rod, a rocking leverarranged in a plane parallel to the plane in which lies the axis of saidrod, a pivot fast with the machine frame for rockingly supporting saidlever at a point intermediate the ends of the latter, a drivingcrankshaft arranged with its axis perpendicular to the direction of theaxis of said pivot, a connecting rod interposed between the crank ofsaid crankshaft and the end of said rocking lever remote from said rod,a spherical head on said end of the rocking lever, and a sphericalrecess at the end of said connecting lever opposite the crankshaft forengaging said spherical head, the other end -Of said rocking lever beinghinged on said pin provided at the lower end of said rod.

References Cited in the le of this patent UNITED STATES PATENTS2,718,859 zeier sept. '27, 1955 FOREIGN PATENTS 467,956 Germany Nov. 5,1928 659,796 Germany May 11, 1938

